The petroleum industry is increasingly turning to heavy crudes, resids, coals and tar sands, i.e., lower grade hydrocarbon (“heavy oil”), as sources for feedstocks. The upgrading or refining of these feedstocks is accomplished by treating the feedstocks with hydrogen in the presence of catalysts to effect conversion of at least a portion of the feeds to lower molecular weight hydrocarbons, or to effect the removal of unwanted components, or compounds, or their conversion to innocuous or less undesirable compounds.
In the hydroconversion process, it is desirable to employ catalyst having sufficient open volume (porosity) for low mass transfer resistance and facilitate efficient through flow of reactors, while at the same the specific area of each catalyst body should be as large as possible to increase exposure of the reactants to the catalyst material. However, a catalyst that is highly porous does not necessarily mean that the catalyst has a lot of surface area. The catalyst may be too porous, having very little in terms of surface area and correspondingly, low catalytic activity in terms of reactive sites.
There is a need for a bulk/unsupported catalyst for use in the hydroconversion of lower grade hydrocarbon with improved performance, i.e., providing high yield conversions with optimum porosity and surface area. There is also a need for a bulk multi-metallic catalyst having sufficient pore volume/size for hydrotreating heavy oil feeds.